A creamy, lightly mashed potato salad bound with tangy Kewpie mayonnaise and studded with paper-thin cucumber, carrot, sweet onion, and ham. Unlike the chunky Western version, the potatoes are deliberately broken down so the salad turns soft and almost fluffy, with a faint vinegar bite from rice vinegar worked into the still-warm potatoes.
Potato salad arrived in Japan during the Meiji era as part of the wave of yoshoku, Western-style dishes reinterpreted for Japanese tastes, but the modern mayonnaise-bound, mashed-potato version only became widespread from around 1955, as mass-produced mayonnaise took hold. Japanese cooks made it their own with Kewpie mayonnaise, the egg-yolk-rich mayo invented in 1925, and by mashing the potatoes far more than Europeans would; today it is a fixture of the home dinner table, the bento box, and the izakaya small-plate menu.
Soft and cloud-like where the potato has been mashed, with little cool crunches of squeezed cucumber and sweet onion breaking through. The Kewpie mayo is richer and tangier than ordinary mayonnaise, and the splash of rice vinegar keeps the whole thing from feeling heavy. Comforting and nostalgic, it eats like a savory custard that happens to have texture.
Seasoning the potatoes with vinegar while they are hot lets the starch absorb the acid and salt deep into each piece, so the flavor isn't just on the surface. Salting and squeezing the cucumber draws out water by osmosis, preventing the salad from going watery in the fridge. Kewpie mayo, made with only egg yolks and rice vinegar, brings more emulsified fat and a sharper tang than whole-egg Western mayo, which is why the texture turns so plush.
Variations
Add hard-boiled egg, sweet corn, or apple for a touch of sweetness; swap ham for crisp bacon; some cooks fold in a little Japanese mustard or a spoon of yogurt for extra tang. Regional home versions vary the vegetables freely, but Kewpie mayo and well-mashed potato are non-negotiable.
On the Palate
Where Japanese Potato Salad sits in the Japanese flavor cloud
Ingredients
Serves 4
How it's made
8 steps · 20 min
- 116 min
Peel 4 medium potatoes, cut into chunks, and boil in salted water 15 minutes until a skewer slides through easily.
- 210 min
While they cook, slice 1/2 cucumber paper-thin, salt it, rest 10 minutes, then squeeze out the water firmly.
Watch outSalt the cucumber and squeeze it bone-dry — skip this and it weeps water that turns the whole salad soupy in the fridge.
- 35 min
Thinly slice 1/4 onion and soak in cold water 5 minutes to mellow its bite, then drain; dice 2 slices of ham and a little carrot.
- 42 min
Drain the potatoes, return to the hot pan, and shake dry over low heat for a minute to evaporate surface moisture.
Watch outShake the drained potatoes dry over low heat until the surface looks matte — leftover water dilutes the mayo and blocks the seasoning.
- 53 min
Mash the warm potatoes coarsely with a fork, leaving some texture, and season with 1 tbsp rice vinegar, salt, and white pepper while still hot.
Watch outSeason with the vinegar while the potatoes are still hot — the warm starch drinks the acid deep in, so flavor isn't just on the surface.
- 65 min
Let the potatoes cool to just warm, then fold in the cucumber, onion, carrot, and ham.
- 73 min
Stir in 3-4 tbsp Kewpie mayonnaise until creamy but not soupy; taste and adjust salt.
- 82 min
Chill briefly and serve mounded, topped with a little extra cracked pepper.
